Process for finishing cellulosic textile materials with n-methylol compounds

ABSTRACT

Finishing treatment of textile materials such as cotton is effected by impregnating such material with a cross-linking, resin-forming, nitrogen-containing methylol compound such as dimethylol urea, dimethylol dihydroxy-ethylene urea, methylol acrylamide in the presence of an acid catalyst, like trichloro acetic acid either alone or preferably in mixture with its salts or a mixture of a thermally unstable acid with a salt of trichloro acetic acid.

United States Patent Bergmann 51 Mar. 21, 1972 [54] PROCESS FOR FINISHING CELLULOSIC TEXTILE MATERIALS WITH N-METHYLOL COMPOUNDS [72] Inventor: Gerhard Bergmann, Niederau, Germany [73] Assignee: Hoesch-Chemie GmbH, Duren, Germany [22] Filed: Mar. 14, 1969 21 Appl. No.: 807,402

[30] Foreign Application Priority Data Mar. 16, 1968 Germany ..'.P 17 19 546.9

[51 Int. Cl. ..D06m 13/34 [58] Field of Search ..8/1 16.3, 115.5, 115.7

[56] References Cited UNITED STATES PATENTS 2,837,512 6/1958 Mantell... ..8/l16.3 X

3,120,507 2/1964 Andrew etal... 3,518,042 6/1970 ...8/163 X Pensa ..8/1 16.3

OTHER PUBLlCATlONS J. T. Marsh, Crease Resisting Fabrics, 1962, Reinhold Publishing Corp., New York, pp. 112- 119.

Primary Examiner-George F. Lesmes Assistant ExaminerT. J. Herbert, Jr. Attorney-McClure, Weiser & Millman [5 7] ABSTRACT 17 Claims, No Drawings PROCESS FOR FINISHING CELLULOSIC TEXTILE MATERIALS WITH N-METHYLOL COMPOUNDS The invention relates to the finishing of textiles in the process of wet, damp or dry cross-linking with nitrogen-containing methylol compounds.

It is known in the finishing of textiles to subject fibrous materials of natural or regenerated cellulose as well as mixed fibers of natural and synthetic fibers to cross-linking in order to give a carefree finish to the goods. For instance, wrinkle re sistance is imparted to cellulosic fabrics with dimethylolurea. It is usually applied with an acidic catalyst to set or affix the monomer to the inner structures of the fibers as a resin, forming an internal finish. In the wet or damp cross-linking process, the textiles are treated to achieve this purpose with a nitrogencontaining methylol compound in the presence of strong acids. The acid catalysis has the effect of causing the reaction of the methylol group with the hydroxyl group of the cellulose, which has the effect of cross-linking the cellulose. As crosslinking catalysts there are used inorganic acids, such as hydrochloric acid alone or in combination with suitable organic acids.

In the dry cross-linking method, it is conventional to carry out the process in the presence of salts which are acid-reacting under the effect of heat. After the cross-linking step has been carried out, it is necessary in the wet or damp cross-linking process to neutralize the acids and to remove them from the textile goods in order to avoid damaging the fibers, which could result from an extended effect of the acids thereon. In contrast to the dry cross-linking method, it is necessary in the damp or wet cross-linking process to follow with an additional past-processing step as well as with a second drying step, which both are required as a result of the required abovediscussed neutralization. Accordingly, this procedure requires additional chemicals and drying energy.

The object of the invention is to overcome the drawbacks of the known method. In accordance with the invention, a method is provided whereby two steps in the above-described conventional process are omitted, namely, the neutralization step and the following required drying step.

These objects are attained in accordance with the process of the invention in the finishing of textiles by a wet, damp or dry cross-linking method with nitrogen-containing methylol compounds in the presence of acid cross-linking catalysts which comprises carrying out the cross-linking of the textile fibers in the presence of an acid cross-linking catalyst which is thermally unstable and then, after the necessary cross-linking has been effectuated, destroying the catalyst by a heat treatment. The acid catalyst is used alone or with one of its several salts.

In accordance with the invention, there are used thermally unstable acids such as organic acids like trichloracetic acid, mesoxalic acid, propiolic acid, tetrolic acid, acetoacetic acid, ethanetricarbonic acid or malonic acid. These acids may be used in amounts of to 50 g./l. Preferred amongst the various organic, heat-sensitive acids is trichloracetic acid because it decomposes into chloroform and carbon dioxide at a temperature in the range of about 80 to 100 C., in a time dependent reaction.

Under the same conditions, the salts of this acid form carbonate. When in accordance with the invention, there is used as a cross-linking catalyst, trichloracetic acid in combination with one of its salts, the acid residue is neutralized concurrently with the decomposition of the acid-forming carbonate of the acid. In this manner, it is possible to shorten the duration of the necessary time for the heat treatment when causing a neutral textile reaction.

Any salt of trichloracetic acid which is heat decomposable can be used including the metal salts thereof like alkaline-, alkaline-earth-, ammonium-, aluminum-, amine-, heavy metal-, sodium or potassium salts.

In accordance with the invention, equivalent results are obtained by the use of other acids than trichloracetic acid, such as organic or inorganic acids in combination with a salt of trichloracetic acid. Suitable for the purpose of the invention are principally the following acids: oxalic acid, formic acid,

hydrochloric acid, phosphoric acid, tartaric acid, and an alkane sulfonic acid or aryl sulfonic acid like ethane or toluene sulfonic acids.

After cross-linking, the decomposition of the acid is accomplished by subjecting the mixture to a short heat treatment at a temperature of about 130 to 140 C. The decomposition of the thermally unstable acid, after it has effectuated its function as a cross-linker, can also be effectuated by holding the temperature at elevated temperatures for a longer period of time.

During the wet or damp cross-linking, it is recommended that the textile which is impregnated with the cross-linking catalyst for the synthetic resin and with the conventional additives be cured by subjecting it to a holding period after it has been reduced to a residual water content. Then the textile is subjected to a short additional thermal post-treatment.

In accordance with the method of the invention, the thermal post-treatment can also follow directly the drying to the desired residual humidity and, thus the holding or curing period can be omitted.

In accordance with the invention, wherein the cross-linking catalyst is used in the dry cross-linking embodiment, the drying and the heat treatment of the impregnated textile goods can be carried out in one process step.

In accordance with a further advantageous embodiment of the invention, it is possible to cross-link the cellulose, for instance, with methylolacrylamide. Also, the finishing and the dyeing of the textile can be carried out concurrently in one step.

In this embodiment, the composition of the acid-salt mixture is so selected that after the thermal treatment in accordance with the invention, an alkaline reaction of the fiber is established.

The chloroform vapors which are generated upon the decomposition of trichloracetic acid are removed in accordance with conventional procedures used in finishing textiles, such as by suction from the dry goods so that the process can be carried out under all the requisite safety requirements.

As is apparent from the above, the invention involves the use of a heat-decomposable acid or its salts in a known process in substitution for the known acidic catalysts. Particularly well suited are those acids or their salts which decarboxylate into gases, such as CO upon heating to about C. or higher and which therefore are the equivalent of trichloracetic acid or malonic acid and their respective salts. Likewise, oxalic acid and its salts can be used.

For aspects known in the prior art, reference is made to: Encyclopedia of Chemical Technology, Kork & Othmer, Vol. 13, Textile Technology pages 904-907, Interscience Publishers, 1954; Textile Chemicals and Auxiliaries (2d Ed) Speel et al., Reinhold Publishers, 1957, pages 142185 and 435, and Man Made Fibers (4th Ed.), 1963, Wiley & Sons, Processing, pages 537-609, which are incorporated by reference.

The following examples are merely illustrative of the invention and are not to be construed as a limitation thereof.

EXAMPLE 1 A mercerized and bleached cotton fabric is treated with 200 g./l. of a 50% dimethyloldihydroxyethylene urea 35 g./l. of trichloracetic acid, and

5 g./l. of sodium salt of trichloracetic acid and the usual amounts of the conventional additive up to a squeeze-off effect (wet load) of about 80% are impregnated on the foulard.

The impregnated fabric is heated to C. for 20 seconds, dried to a residual water content of 8% and, after a 20-hour curing period, the fabric is subjected for one minute to a temperature of C.

' EXAMPLE 2 The same fabric as in Example 1 is treated with the excep tion that the catalyst mixture is as follows:

40.5 g./l. of sodium salt of trichloracetic acid, and

20 g./l. of 39% aqueous hydrochloric acid.

EXAMPLE 3 Another similar cotton textile material is treated as above, the catalyst mixture is trichloracetic acid in an amount of 20 g./l.

The products exhibit upon a neutral reaction the characteristic values for a wet cross-linking. The acid content of the textile pieces showed a loss of only 10% under the stated conditions. The major amount of the tri-chloracetic acid was removed upon the thermal post-treatment which followed.

The amount of acid used can vary over wide ranges such as to 80 g./l., preferably to 50 g./l. of the liquid mixture for treating the textile.

EXAMPLE 4 In Examples 1 and 3, when the trichloracetic acid is replaced by malonic acid, like results are obtained.

EXAMPLE 5 Examples 1 and 2 are repeated using the sodium salt of malonic acid.

Likewise, the potassium salt thereof can be used.

EXAMPLE 6 The same fabric as in Example 1 is treated with a catalyst mixture of I50 g./l. ofa 50% methylolacryl amide 20 g./l. of trichloracetic acid, and

25 g./l. of sodium salt oftrichloracetic acid. The fabric is foulardised, dried at 80 C., subjected to a thermal treatment at 150 C. for 5 minutes and steamed at 43 p.s.i. for 2 minutes.

EXAMPLE 7 TO 9 Example l is repeated using 36.5 g./l. of sodium salt of trichloracetic acid and 10 g./l. ofoxalic acid, or

45.03 g./l. of sodium salt of trichloracetic acid and 5 g./l. HCl 100%), or

61.4 g./l. of sodium salt trichloracetic acid and g./l. of formic acid instead trichloracetic acid and its sodium salt like results are obtained.

lclaim:

1. In a textile finishing process by cross-linking a textile material comprising a cellulosic textile by the reaction with a resin-forming, cross-linking nitrogen-containing methylol compound in the presence of an acid cross-linking catalyst, the improvement which comprises carrying out said crosslinking reaction in the presence of an acid cross-linking catalyst selected from the following: trichloro acetic acid, a mixture of trichloro acetic acid and its salts, and a mixture ofa cross-linking acid and a salt of trichloro acetic acid, and heating the cross-linked textile material to decompose the crosslinking catalyst, thereby eliminating subsequent neutralization of the cross-linked textile material.

2. The process of claim 1, in which the cross-linked textile material is heated to a temperature of at least l00 C.

3. The process of claim 1, in which the salt of trichloro acetic acid is its alkali metal salt.

4. The process of claim 1, in which the mixture of a crosslinking acid and a salt of trichloro acetic acid is a mixture of hydrochloric acid and an alkali metal salt of trichloro acetic acid.

5. The process of claim 1, in which the mixture of a crosslinking acid and a salt of trichloro acetic acid is a mixture of oxalic acid and an alkali metal salt of trichloro acetic acid.

6. The process of claim 1, in which the mixture ofa crosslinking acid and a salt of trichloro acetic acid is a mixture of formic acid and an alkali metal saltpf trichloro acetic acid.

7. The process of claim 1, in which the cross-linking, resinforming, nitrogen-containing methylol compound is dimethylol urea.

8. The process of claim 1, in which the cross-linking, resinforming, nitrogen-containing methylol compound is dimethylol dihydroxy ethylene urea.

9. The process of claim 1, in which the cross-linking, resinforming, nitrogen-containing methylol compound is methylol acrylanide.

10. The process of claim 1, additionally including the steps of curing the heated and dried cross-linked textile material and subjecting it to a further heat treatment at a temperature of at least about C.

11. The process of claim 1, in which the proportion of the salt of trichloro acetic acid and the cross-linking acid in the acid catalyst is such that, after heating and drying the impregnated textile material, an alkaline reaction of the textile material is established.

12. The process of claim 1, in which the textile material to be subjected to the finishing treatment is a cellulosic textile material.

13. The process of claim 1, in which the textile material to be subjected to the finishing treatment is a cotton fabric.

14. In a process for the finishing of a textile material comprising a cellulosic textile, the steps which comprise impregnating the textile material with an aqueous solution comprising a cross-linking, resin'forming, nitrogen-containing methylol compound and an acid cross-linking catalyst selected from the group consisting of trichloro acetic acid, a mixture of trichloro acetic acid and its salts, and a mixture ofa thermally unstable cross-linking acid and a salt of trichloro acetic acid and heating and drying the impregnated textile material to cause cross-linking of the textile material with the nitrogencontaining methylol compound and to decompose the crosslinking catalyst.

15. The process of claim 14 which includes the step of admixing the acid cross-linking catalyst with the cross-linking nitrogen-containing methylol compound prior to the crosslinking reaction.

16. The process of claim 15 which is carried out without post-neutralization.

17. The process of claim 15 which is carried out without postrinsing. 

2. The process of claim 1, in which the cross-linked textile material is heated to a temperature of at least 100* C.
 3. The process of claim 1, in which the salt of trichloro acetic acid is its alkali metal salt.
 4. The process of claim 1, in which the mixture of a cross-linking acid and a salt of trichloro acetic acid is a mixture of hydrochloric acid and an alkali metal salt of trichloro acetic acid.
 5. The process of claim 1, in which the mixture of a cross-linking acid and a salt of trichloro acetic acid is a mixture of oxalic acid and an alkali metal salt of trichloro acetic acid.
 6. The process of claim 1, in which the mixture of a cross-linking acid and a salt of trichloro acetic acid is a mixture of formic acid and an alkali metal salt of trichloro acetic acid.
 7. The process of claim 1, in which the cross-linking, resin-forming, nitrogen-containing methylol compound is dimethylol urea.
 8. The process of claim 1, in which the cross-linking, resin-forming, nitrogen-containing methylol compound is dimethylol dihydroxy ethylene urea.
 9. The process of claim 1, in which the cross-linking, resin-forming, nitrogen-containing methylol compound is methylol acrylanide.
 10. The process of claim 1, additionally including the steps of curing the heated and dried cross-linked textile material and subjecting it to a further heat treatment at a temperature of at least about 140* C.
 11. The process of claim 1, in which the proportion of the salt of trichloro acetic acid and the cross-linking acid in the acid catalyst is such that, after heating and drying the impregnated textile material, an alkaline reaction of the textile material is established.
 12. The process of claim 1, in which the textile material to be subjected to the finishing treatment is a cellulosic textile material.
 13. The process of claim 1, in which the textile material to be subjected to the finishing treatment is a cotton fabric.
 14. In a process for the finishing of a textile material comprising a cellulosic textile, the steps which comprise impregnating the textile material with an aqueous solution comprising a cross-linking, resin-forming, nitrogen-containing methylol compound and an acid cross-linking catalyst selected from the group consisting of trichloro acetic acid, a mixture of trichloro acetic acid and its salts, and a mixture of a thermally unstable cross-linking acid and a salt of trichloro acetic acid and heating and drying the impregnated textile material to cause cross-linking of the textile material with the nitrogen-containing methylol compound and to decompose the cross-linking catalyst.
 15. The process of claim 14 which includes the step of admixing the acid cross-linking catalyst with the cross-linking nitrogen-containing methylol compound prior to the cross-linking reaction.
 16. The process of claim 15 which is carried out without post-neutralization.
 17. The process of claim 15 which is carried out without postrinsing. 